Bird bath heater



FIG. 1 is a perspective view of a bird bath heater showing my new design;

FIG. 2 is another perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a back view thereof;

FIG. 5 is a left view thereof;

FIG. 6 is a right view thereof;

FIG. 7 is a top plan view thereof;

FIG. 8 is bottom plan view thereof; and,

FIG. 9 is an enlarged view of portion of FIG. 7 .

The dot-dash broken lines in FIGS. 7 and 9 represent the boundary of the enlarged portion and form no part of the claimed design. The broken lines shown in the drawings are included for the purpose of illustrating portions of the bird bath heater that form no part of the claimed design. 

CLAIM The ornamental design for a bird bath heater, as shown and described. 